Quantitative and Qualitative Analysis of Palatal Rugae Patterns in Bhopal Division: A Retrospective Cross-Sectional Study

ABSTRACT

Objective:

The goal of this investigation is to assess the palatal rugae patterns in male and female participants from the Bhopal Division population.

Material and Methods:

A randomly selected cohort of 104 individuals, consisting of 47 males and 57 females, was included in the study. Both metric and non-metric characteristics of the palatal rugae were documented and analyzed using two-sample t-tests and chi-square tests, with a significance threshold set at 5%.

Results:

No significant difference was observed in the total number of rugae between genders. However, the mean number of primary rugae was significantly higher in males (P = 0.038). In contrast, females exhibited a higher mean number of vertical (P < 0.001) and fragmentary rugae (P = 0.004), with these differences achieving statistical significance.

Conclusion:

The rugae pattern demonstrates potential as a gender-differentiating characteristic, serving as a supplementary method to traditional techniques such as cranial anthropometry and dental analysis.

INTRODUCTION

Identification can be challenging in road traffic accidents, terrorist incidents, and natural disasters. Common methods for identification include visual recognition, fingerprints, DNA, and dental records. “Rugae” are anatomical structures formed by mucosal folds on the anterior palate.[1] They extend slightly posteriorly and anteriorly from the incisive papilla on either side of the midpalatal suture.[1,2] These patterns are unique to individuals and remain consistent throughout adulthood. Typically, there are 3 to 6 folds on each side, which may be asymmetric. Fold length is measured transversely from the midpalatal suture to the endpoint. Rugae patterns are categorized by length: Primary (5–10 mm), Secondary (3–5 mm), and Fragmentary (<3 mm).[3,4] Rugae shapes fall into four categories: straight, curved, wavy, or circular, with orientations determined relative to the mid-palatal raphe (MPR) [Figure 1].[4,5] This research aimed to assess the quantitative and qualitative parameters (size, shape, and direction) of palatal rugae in a sample from the Bhopal division.

Figure 1.

Showing type of rugae

MATERIAL AND METHOD

Pre-orthodontic dental casts from individuals of various social classes in the Bhopal Division were analyzed. The palatal rugae of 47 males and 57 females, aged 14 to 70, were highlighted using a 0.1 μm tip HB pencil. The mid-palatal raphe was identified, and the number of rugae on each side was recorded. Metric and non-metric features of the palatal rugae were documented using a standardized form. Participants excluded from the study were those under the age of fourteen, those with congenital deformities (e.g. cleft palate), a history of orthognathic surgery, allergies to impression materials, bone and soft tissue protuberances, active lesions, deformities, scars, or trauma to the palate. Ethical clearance was obtained from the Institutional Ethics Committee (IEC).

RESULT

The total number of participants was 104. All descriptive data are provided in detail in Table 1.

Table 1.

Aggregate count of rugae, along with its mean±standard deviations

Rugae Data	Rugae Metrics		P on independent t test
	Male N=47	Female N=57
Mean SD	10.6 (1.7)	10.4 (1.8)	0.502
Total Rugae count	499	592

Shape of rugae

The most common rugae pattern observed is the straight type (mean for males: 4.8; mean for females: 5), followed by the curved rugae pattern (mean for males: 3.7; mean for females: 3.8). The wavy pattern is also less common (mean for males: 1.5; mean for females: 1.5), while the circular rugae type is the least common in both males and females (mean for males: 0.2; mean for females: 0.3) [Table 2].

Table 2.

Distribution of different shapes of rugae, direction of rugae and Length wise distribution of rugae, its mean value, standard deviation and P

Rugae Pattern Categories	Type of rugae	Mean number of rugae per person (SD)
		Male N=47	Female N=57	P on independent t test
Shape	Straight	4.8 (1.8)	5 (1.7)	0.547
	Curved	3.7 (1.3)	3.8 (1.3)	0.81
	Wavy	1.5 (0.9)	1.5 (0.8)	0.722
	Circular	0.2 (0.4)	0.1 (0.3)	0.114
Direction & Orientation	Forward	5.8 (2.3)	6.1 (2.2)	0.575
	Backward	2 (1.5)	1.9 (1.4)	0.614
	Horizontal	2.5 (1.5)	2.1 (1.7)	0.2
	Vertical	0 (0)	0.3 (0.6)	<0.001*
Length of Rugae	Primary	8.7 (1.2)	8.1 (1.8)	0.038*
	Secondary	1.3 (1)	1.8 (1.5)	0.081
	Fragmentary	0.4 (0.5)	0.8 (0.8)	0.004*

*Significant

Direction of rugae

Table 2 shows the direction and distribution of rugae on both sides of male and female samples. On comparing the data from both sides, vertical rugae patterns are the least common (mean for males: 0, mean females 0.3). The mean value for horizontal pattern’s is 2.5 among males, which is higher than the mean value of 2.1 in females. The backward pattern has a similar mean value as to the horizontal pattern (mean for males: 2, mean for females: 1.9). The forward pattern is the most common in both males and females (mean for males: 5.8, mean for females: 6.1).

Lengthwise distribution of rugae

Primary rugae are the most common in both genders (mean for males: 8.7; mean for females: 8.1). Secondary rugae are the second most common pattern (mean for males: 1.3; mean for females: 1.8). Fragmentary rugae are the least common (mean for males: 0.4; mean for females: 0.8) [Table 2].

DISCUSSION

Palatal rugae are notable for their steadiness and endurance, making them invaluable for forensic identification. Their patterns and counts do not significantly change throughout a person’s life and can remain identifiable for up to seven days post-mortem, aiding in post-mortem verification.

In our study, we observed that palatal rugae patterns are diverse rather than uniform. The average rugae count was 10.6 for males and 10.4 for females, in contrast to a study in Meerut, which reported averages of 7.04 and 6.8, respectively. Other studies conducted in Andhra, Lucknow, and Gujarat populations also revealed no significant gender differences in rugae numbers.[4,5,6]

Regarding pattern types, our study identified straight and curved rugae as the most common. Research by Byatnal et al.[7] reported that wavy rugae were the most prevalent, followed by straight rugae, across various Indian populations including Andhra, Karnataka, Madhya Pradesh, and Maharashtra. Conversely, a study on the Gujarati population found that straight rugae were most common, followed by curved, wavy, and circular patterns. In the Maharashtrian population, straight rugae were the most prevalent, followed by wavy and then curved rugae, with statistically significant differences noted.

In terms of direction, our study indicated a predominance of forward-directed rugae, aligning with findings in Kerala, Manipur, and Maharashtra populations. Primary rugae were prevalent in both genders, similar to findings in Gujarati and Maharashtrian studies.[8,9]

Overall, our research supports the conclusion that there is no notable difference between males and females regarding the number or type of palatal rugae. These findings underline the consistency of rugae patterns in forensic identification, although regional variations do exist.

CONCLUSION

The purpose of this research was to compare rugae patterns between males and females within a sample population from the Bhopal division. The analysis revealed no significant difference in the total number of rugae between the two genders. However, a higher mean number of primary type rugae was observed in males (P = 0.038), while females exhibited significantly greater mean numbers of vertical (P < 0.001) and fragmentary types (P = 0.004). These differences are statistically significant, suggesting that rugae patterns could serve as a supplementary method for gender estimation. Nonetheless, further studies with larger sample sizes are recommended to validate these findings.

Conflicts of interest

Nil.

Funding Statement

Nil.